One vertex per element, one color per generator, with an edge from x to x·s.
(2,5)(6,8)(9,10)(11,12)(13,18)(14,16)(15,17)(19,20)(21,24)(22,23)(25,26,31,34)(27,35,30,32)(28,29,33,39)(36,40,38,37)(1,2,4,5)(3,6,7,8)(9,11,14,17)(10,15,16,12)(13,19,22,24)(18,21,23,20)(25,27,31,30)(26,32,34,35)(28,36,33,38)(29,37,39,40)(10,16)(11,17)(18,23)(19,24)(25,26,31,34)(27,35,30,32)(28,29,33,39)(36,40,38,37)(1,3,4,7)(2,6,5,8)(9,10)(11,15)(12,17)(13,18)(14,16)(19,21)(20,24)(22,23)(25,28,31,33)(26,29,34,39)(27,36,30,38)(32,37,35,40)(9,12,14,15)(10,17,16,11)(13,21,22,20)(18,19,23,24)(25,29)(26,33)(27,37)(28,34)(30,40)(31,39)(32,38)(35,36)(9,13,14,22)(10,18,16,23)(11,19,17,24)(12,20,15,21)(25,30,31,27)(26,32,34,35)(28,38,33,36)(29,37,39,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.